[How can metastatic bone involvement be assessed?].

The first intention imaging modality for detecting bone metastases of non small cell (NSC) bronchogenic carcinoma is bone scintigraphy using technetium-99m pyrophosphate or diphosphonates. This test has a high sensitivity but equivocal images may lead to complementary tests including magnetic resonance imaging (MRI) or bone biopsy. Based on bone metastases prevalence, scintigraphy is recommended for patients entering a therapeutic trial, having bone pain, having a non characteristic bone abnormality on radiography or CT, having a non epidermoid histology or having associated pathologies increasing the risk of surgery. The utility of bone scan is questionable for patients having a Stage I or II epidermoid cancer, having already evidence of bone metastases or for whom the result of the bone scan will not change the therapeutic management. After a negative bone scan, there will be probably an indication for MRI at search of small infra-scintigraphic osteo-medullary metastases.